Is there way to return null valued rows when when querying joined table - sql

Question

I have two tables: users table with id, name columns and events table with id, content and userId columns.
I am trying to query a table that return joined information from these two tables with name and events columns where events would represent an array of content fields corresponding to a user.
This is the query I am running:
select
name, group_concat(content) as events
from
users
left join
events on id = userId
group by
userId
order by
id
However rows with null values are not being returned except of just one row. What am I doing wrong?
Users table
[
{
"id": 1,
"name": "Hugo Powlowski"
},
{
"id": 2,
"name": "Jeremy Littel II"
},
{
"id": 3,
"name": "Eleanor King"
},
{
"id": 4,
"name": "Rogelio Jacobson"
},
{
"id": 5,
"name": "Jerald Rowe PhD"
},
{
"id": 6,
"name": "Robyn Tromp"
},
{
"id": 7,
"name": "Norman Zboncak"
},
{
"id": 8,
"name": "Mr. Kristy Orn"
},
{
"id": 9,
"name": "Mrs. Olivia Trantow"
},
{
"id": 10,
"name": "Daniel Lebsack"
}
]
Events table
[
{
"eventId": 3,
"content": "hello",
"userId": 7
},
{
"eventId": 12,
"content": "rulsan berden",
"userId": 1
}
]
Joined table
[
{
"name": "Hugo Powlowski",
"events": "rulsan berden"
},
{
"name": "Jeremy Littel II",
"events": null
},
{
"name": "Norman Zboncak",
"events": "hello"
}
]

Answer 1

You should group by the column in the parent table, not the table being left joined, so that the values will never be null.
So change GROUP BY userid to GROUP BY users.id.

Answer 2

Try to use a nested SELECT, this should return null for the users without any event:
select
u.name,
SELECT(
group_concat(content)
FROM
events
WHERE
userId = u.id
) as events
from
users u
order by
u.id